Energy control arrangement



FIP8212 XR hawdzo March 8, 1932. R H, Y 1,848,220

ENERGY CONTROL ARRANGEMENT Filed Aug. 26. 1927 Coupled 2'6 27m aim of flaw/2270:

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A 'Appfication filed August, serial flm fljlaia (.This invention relates to signaling system and particularly to transmission systems-employing devices for automatically-controlling the energy levels therein, 4 v I ,j i Circuits for the transm'ission of voicefife quency signals, such as telephone circuits or the like, may undergo variations in attenua: tion due, for example, to weather changes; Corrections must be applied to such circuits in order to maintain the circuit equivalents substantially constant. One form of reg lating circuit for applying the desired corrections may consist of .one or moreflight valves of, for example, the selenium type.

:- Such valves normally exhibit ahigh impedance in darkness and yet they undergo a substantial change in impedance when exposed to light. Accordingly, 'such valves maybe arranged to increase or decrease the quantity of the energy flowing in a signalingsystem as conditions necessitate. r 'f'fr Accordingly, it is one of the objects oft'his invention to provide twolight 'cel'ls,-either of which may be exposed tolight in orderto change .in impedance, to thereby regulate the 'energy v.ilovving through a transmission circuit. f 1 It is another .object of th's'inventionto couple the energy adjusting means of a trans;- electrical motor softhat when either of two light valves become energized,the motor may be set. into rotation in one direction or in the other to correspondingly vary theenergy adjusting means. f ""It is a further object'of this invention-to pick up asmall portion of the energy flowing jrom an input circuit'into an output circuit, .whi ch are interconnected by an energy'adjusting means, to rectify the energy sopick'ed up and cause that ener to operate one light control valve oranot er, to accordingliv'reamotor inone irecfti n .ori the iother, arid-to thereby 'cause the energy adjusting means-to, be correspondingly varied. W 3

While this invention willibe-pointed bu't with particularity in the; appended claimsythe invention itself, both asto' its fuitherobgeets and features, will be better understoodjuim restlessris easementsing, when read inconnectioh with the acc0mp anying drawing showing one embodiment of the invention merely for the purpose of illustration.

Referring to the-drawing,-an input circuit E is shown connected through -an energy adjusting means G'which may, 'foriiexample; be a potentiometer, as shown. Alternating current'which may be transmitted'for thepurpose of actuating the adjusting mechani put circuit E to the output circuit E in the direction indicated by the arrows} In this invention the level oi the energy of this cur- "rent" in the input'circuit ina vary within-eerta'in limits andit'is'desire ,to keep thelevel ofthis energy as applied to the output cir- Quit within small limits of variation, preferably by. automatic means. The potentiometer or energyadjusting meansjn'iay' have suffi- 'cient range of variation on manual adjustmentto efiectby the level of the energy-flowing into .the output circuit E, but in this "invention means will be provided for, auto- {natica'lly changing the position of the po- -entiometer or energy adjusting means accordancewith hanges the level of energyflowin in thefitransmission circuit. motor aving an armature A'and a field coilW'isso related tothe tern that armatureA; m'ja'y be caused to rotate in one direction or intheother asfound "desirable. The jieldcoil Wof the motor is supplied with current from af's'ource B -which may be of the alternating current type as "well as I of the direct smear type as shown. The armature'%j;of thisniotor is mechanically coupled 'to the-movable arm of the potentiometer G, preferably through a train of gears (not imam-3; Th w en t armature A tatesfi-n pie directionythe 'energy passing rump h the otentiometer may be inand w en theiarmature rotates inthe "opposite-* directioirf the energy passing 'through 'potentidmeter G'may be decreased. A small portion of "the output circuit IE applied towthe 'pri- "mary ofa transformer T theimped- "ance ;-e the"primarywinding being preferably substantiafly hi hpto thereby limit the to an output circuit E sm will flow from the inthe current transmittedto amount of energy so applied. The current applied to the primary winding of transformer T however, becomes similarly applied to the input circuit of a rectifying device which may, for example, be a rectifier tube ofth'e three-electrode type. Thisenergy is accordingly applied between the grid and filament of a rectifier tube V. The filament ofthe tube V is heated to an electron emitting temperature by a-battery B A condenser C shown in dotted lines, bridges the secondary winding of transformer T Thus, a tuned circuit is provided, including the secondary windin of a transformer T and condenser C whic may be employed for selectively applying, between the grid and filament of the vacuum tube V current of the frequency which is to be transmitted for the purpose of actuating the adjusting mechanism, thus separating it from currents of other unwanted frequencies which may also be transmltted at the same time, such as, for example, currents of frequencies directly in volved in the transmission of speech. It will be understood, however, that any other rectifying device may be employed instead of vacuum tube V within the scope of his invention.

The plate circuit of the vacuum tube V includes a meter J, resistances R and R a battery B and the filament and plate of the vacuum tube V. This is a direct current circuit. A by-pass for alternating currents is provided by a condenser C shown connected between the plate and filament of vacuum tube V. The meter J of this circuit may have a dial which is graduated to indicate whether the energy flowing through this circuit is normal, high or low. When normal current flows through meter J, its pointer may rest in position N. When current of higher magnitude flows therethrough, the pointer of this meter may reach the H position, and

7 when current lower than normal flows therethrough, this pointer may reach the L position. Thus, when the pointer of this meter is at its N position, the level of the energy in the output circuit E is normal. When the pointer reaches the H position, the apparatus of this invention will be set into operation to cause the potentiometer or energy adjusting means G to be lowered and to accordingly decrease the level of the energy in the output circuit E Conversely, when the pointer of meter J reaches the L position, the apparatus of this invention will be again set into operation, causing the potentiometer or energy adjusting means G to become increased, to there by increase the level of the energy in the out put circuit E Two galvanometers which may be, for example, of the DArsonval type bridge resistances R,.and R These galvanometers have moving coils A and A interposed between pole pieces and P and between pole pieces crease in the potential drop across resistance R and in a counter-clockwise direction 'with a'decrease in the potential drop of resistance B A source of light which may be an electrical lamp is indicated by the reference character F. The filament of this lamp is connected to a battery 13,. Light of source F impinges upon mirrors M and M and if these mirrors are in their normal positions, this light will be reflected therefrom along the lines N and N respectively. A change in the potential across either the resistance R or resistance R will cause the rotation of the corresponding moving coil to effect a corresponding deviation of the reflected light from the associated mirror.

Three light valves or cells are designated by the reference characters S S and S These valves or cells may be of the selenium t pe, each exhibiting a high impedance in arkness and a substantially lower impedance when exposed to light. Light cell S is positioned so as to be affected by the reflected beam of light from mirror M when this mirror rotates in a counter-clockwise direction. Light cell S is acted upon by reflected light when mirror M is rotated through a predetermined angle in the clockwise direction. Similarly, cell S becomes exposed to reflected light when mirror M is rotated in a counter-clockwise direction. The windings of relays D D and D are connected to the light cells S 'SZ and S respectively. Each winding remains deenergized until the corresponding light cell has become exposed to light of source F reflected by one of the mirrors' "Relays I).,,D,, and D are associated with relays D1. D and D respectively, each of these relays becoming operative when the winding of the associated relay has become energized due to the action of the associated light cell.

When the level of the energy in the in ut circuit E decreases from its normal va ue, the magnitude of the rectified current will also decrease. The pointer of meter J will move to the left of position N, thereby indicating the magnitude of the difference between the normal current in the input circuit E, and itsvalue at the time of measurement. The potential drops of resistances R and R will become decreased and will afiect the rotation ofmirrors M, and M in a counternam clockwise direction, the E it ti ijfb :ing proportional to the difference b ween the normal current wvhichmay flow through the input circuit E and the current which flows through that circuit at theitime of measurement. If the rotation of'the mirror M in a counterclockwise direction is great enough to cause the'beam of reflected light to fall upon light cell S ,'this :cell will under- 'go a'substantial change inimpedance,-causmg the energization of the winding of relay D current flowing throufih the-winding of relay D, from a battery" Ihe armature of relay D will accordingly become attracted, causing the operation of relay D current flowin through the winding of D from-battery The two armaturesof relay D which are mechanically coupled, are so connected to the armature Aofthe motor as to close a circuit to cause its rotation. Thus, current flows from the "battery B through onset the armatures of relay 1),, through the armature of relay D armature A of the motor, the second armature of relay D and ground. Due to the coupling of armature A of the motor and the potentiometeror energy adjusting means G, the rotation of armature A in'the proper direction 'will cause an increase in the energy flowing through-the potentiometer or energy adjusting means G. The armature A of the motor will continue to rotate until the current rectified by the vacuum tube V is increased sufiiciently to cause the rotation of mirror M by the amount necessary to remove the reflected beam of light from light *valve S When the reflected light is removed from cell S its resistance will 1ncrease substantially and the current flow ng therethroughand through the winding of relay D will be insufiicient t0"mainta1n'1t operated, whereuponthe armature of relay D will become released.- Thereupon', the armatures of relay "D4 '-'will become released and the armature Act the motor will fail to continudin'rotation." f

In order to prevent the moving coil Ai of thegalvanometer associated with resistance 11 from rotating so far inacounter-clocliwise direction due to an exceedingly large decrease inthe level of the alternating current in the input circuit 131 so that the reflected beam of light may pass beyond light cell S a mechanical stop, such as'K, maybe provided, in such a position that the maxilmum rotation of the counter-clockwise di- ,rection of the armatureflh will caus'ethe beam of reflected light to fall upon light cell S and to remain in that position. i If, on the other hand,-the level of the energy in the input circuit E1 increases beyond 'its normal value, the magnitude of the rectified current will iner set ereby increasing :the: indication :at 1-. meter 4L1: Ai mat ure's J01 moving coils A and A of the respective galvanometers will be rotated in clockwise direction. Thus, armature A, may rotate sufliciently to cause the reflected beam of light to illuminate light cell S Light cell S then undergoes a substantial change in impedance, causingthe operation of relay D Attractime the armature of relay D will cause the-operation of relay D and will thereby cause the armature A of the motor to rotate in the opposite direction. C0nsequently,the potentiometer or energy adjusting means which is' coupled to the armature A of the motor will be moved in the proper direction to decrease the energy level at the output circuit E The armature A of the motor will continue to rotate until the magnitude of the rectifiedcurrent approaches its normal value, reflected light being then deviated so as to cease to illuminate light cell S Accordingly, the impedance of light cell S will become greatly increased, causing the release of relay D as well as relay D and stopping the rotation of armature A of the motor. To prevent an excessive rotation of the moving coil A; in a clockwise direction a stop K may be provided, reflected light impinging upon light cell S while moving coil A remains fixed against stop K The H and L positions on meter J indicate the limits at which the armature A of the motor is started in rotation in the process of readjusting the energy flowing through the potentiometer G. These limits correspond to a definite magnitude of resistance shunting the moving winding, such as A of one of the associated galv'anomet-ers. These limits also correspond'to a certain tension in the spring holding the moving armature of each galvanometer in a proper position in equilibrium against the-torque produced by the flow of current therethrough; Obviously, ,thes'e limits may made wide or narrow, as .found necessary, by changi both the value of the resistance in shunt with each galvanometer and the tension of the spring at the galvanometer. Thus, iftheselimitsare to-be made .wider, the magnitude of'the resistance IR should be decreased as well as the tension of the spring at the galvanometer. A decrease inthe magnitude of the resistance R causes the application oi a smaller potential drop to the galvanometer, resulting in the production of a smaller torquefwhich req'u'ires a reduced spring tension to establish a balance of the galvanometer in 'thenormal position, ,and resulting further in the necessity for a larger change in rectified current "to be suiiicient to illuminate Jone- 'or-th other of the light cells, Obviously, if these limits are tofbe made narrower','"the magnitudepf the resi'stance'R should be increased as well as :the' tension of the s ring at the moving coil .A of thexas'sociate' "galvandmeter.

The second galvanometer'shulitingilfesis tanceR is provided rtoirender the adjustingmechanism inoperative when the rectified current falls greatly below the normal value. Thus, when the level ofzthe energy inthe input circuit IE. decreases, the armatures A and A rotate in a counter-clockwisedirection,- as has been mentioned herein above. Resistance ,R may, however, 'be smaller in magnitude than resistance R Accordingl armature A: will be less sensitive than and will move more slowly. The sensitivity of armature A may be adjusted so that the beam of light reflected from M will not fell upon light cell S until the rectified current has dropped to apre'determined low value. Such a great drop in the'rectified current maybe due to a change in the level of the energy of the transmission circuit so suddenly as to prevent correction by the energy adjusting means in the usual manner. Such a steep drop in the rectified current may also be due to the fact that the energy level at the transmission circuit has fallen beyond the point where a correction may conveniently be applied. When the light cell S becomes illuminated, relay D will become operated, its armature attracted, causing the operation of relay D The attraction of the armature'of relay D opens the circuit in series with the motor so that the armature A cannot be started in rotation. When this occurs, the armature A of the motor cannot start in rotation even though the light cell S has become exposed to reflected light.

A light cell of the selenium type may be made by depositing light-sensitive selenium upon aconsiderable length of two wires connected in parallel, thus creating numerous paths'in parallel from wire to wire through the selenium. The wires may of course e wound in such a manner as to confine the cell to dimensions of convenient proportions. The sensitivit of such a cell, that"is,the ratio of its con uctivity when exposed to light to its conductivity in darkness, depends amon other things, on certain processes employed in its manufacture. It is to be understood, however, that any other light cell,'as, for example, a: photoelectric cell, may be employed in thisinvention instead oftheselenium cell or that any other device may be employed instead ofthe selenium cell described herein, particularly if that device ,undergoes a substantial change in impedance'when exposed to light, within the scope of this invention' a 4 While this invention has been pointed out in one particular embodiment merely for the purpose of illustration, it is to be distinctly understood that the general principles of this invention may be applied to other and, widely lvaried organizations without departing from the spirit of the invention andthescopeof the PPende'dclaimss i nuaaao (1-1. The combination of a source of current of varying amplitude, a mirror which refiects incident light at an angle corresponding to the difference in amplitudes between the instantaneous value of the current of said source and an arbitrary and predetermined value,.a first light cell which undergoes a substantial change in impedance when the refiected light makes a predetermined angle with respect to :the incident light in a clockwise direction, a second light cell which similarly undergoes a substantial change in impedance-when the refiectedlight makes a different predetermined angle with respect to the incident light in a counter-clockwise direction, a motor, means for rotating the motor in one direction when the first light cell is acted upon,'means for rotating the motor in the opposite direction when the second light cell is acted upon, and a gain control device associated with said source of current whose gain may be changed a predetermined amount in accordance with the rotation of said motor. 7

2. The combination of two mirrors, means for revolving said mirrors, a source of light transmitting a beam simultaneously incident upon said mirrors, three selenium cells each of which may be energized when light of said source is reflectedthereupon, one cell being energized when the first mirror revolves through a predetermined arc in one direction, the second cell being energized when the first mirror revolves in the opposite direction through a predetermined arc, the third cell being energized when the second mirror revolves through a predetermined arc in the first-mentioned direction.

3. In a signaling system, the combination of a source of light, a mirror receiving a beam of light from said source, two light sensitive cells on opposite'sides of the normally reflected beam of light, a source of signaling energy the level of whichmay vary, means for rectifying a portion of the said signaling energy,.a resistance through which the rectified current may flow, and means coupled to said resistance and responsive to an increase in the level'of the rectified'current by a predeterminedamount to rotate the mirror in one direction andcause a substantial change in the impedance of one of the light cells, said means being alsoresponsive to a decrease in the level of the rectified current by a predetermined amount to rotate the mirror in the opposite direction and cause a substantial change in the impedance of the other of the light cells. V

4. The combination of a source of light, a mirror upon which falls the light of said source, two light responsive devices on opposite sides ofthe beam of light reflected by said mirror, each light responsive device undergoing a substantial change in resistance when the reflected beam of light falls thereon, a transmission circuit in which the level of the energy transmitted therethrough may vary, a. vacuum tube device for rectifying a portion of the energy of said transmission circuit, means responsive to an increase in the level of the rectified energy above a predetermined limit to rotate the mirror in one direction and throw the reflected beam of light upon one of the light responsive devices, means responsive to a decrease in the level of the rectified energy below a predetermined limit to rotate the mirror in the opposite direction so as to throw the reflected beam of light upon the other of the responsive devices, a. motor, and means to rotate the motor in one direction or the other in response to a change in the resistance of one light responsive device or the other.

5. The combination of a source of light, a mirror receiving a beam of light from said source, two light cells on opposite sides of the beam of light reflected by said mirror, each light cell undergoing a substantial change in impedance when the reflected beam falls thereon, a source of current of variable amplitude, means for rectifying a portion of the current of said source, means responsive to an increase in the amplitude of the rectified current above a predetermined value to rotate the mirror in one direction so that the reflected beam may fall upon one light cell, means responsive to a decrease in the amplitude of the rectified current below a predetermined value to rotate the mirror in the opposite direction so that the reflect-ed beam may fall upon the other light cell, and a motor which may be rotated in one direction in response to a change in the impedance of one light cell and which may be rotated in the opposite direction in response to a change in the impedance of the other light cell.

6. In a signaling system, the combination of a source of current representing signals the level of which may vary. means for rectifying a portion of the current of said source, a mirror upon which a source of light impinges, means responsive to the rectified current for rotating the mirror through an angle corresponding to the difference in amplitude between the instantaneous value of the rectified current and a predetermined value, a first light cell which substantially changes in resistance when the reflected light makes a predetermined angle with respect to the incident light, a second light cell which also substantially changes in resistance when the reflected light makes a different predetermined angle with respect to the incident light, and means to increase the level of the current emanating from said source when the first light cell changes in resistance and to decrease the level of the current emanating from said source when the second light cell changes in resistatnce.

7. The combination of a source of current of varying amplitude, a potentiometer connected to said source of current to control the level of emitted current, a mirror which reflects incident light at an angle corresponding to the difl'erence in amplitudes between the instantaneous value of the current of said source and an arbitrary and predetermined value, a first light cell which undergoes a substantial change in impedance when the reflected light makes a predetermined angle with respect to the incident light, a second light cell which similarly undergoes a substantial change in impedance when the reflected light makes a diflerent predetermined angle with respect to the incident light, a motor which is coupled to said potentiometer, means for rotating the motor in one direction in response to a substantial change in impedance in the first light cell, and means for rotating the motor in the opposite direction in response to a similar change in impedance in the second light cell.

8. The combination of a source of current of varying amplitude, gain control means connected to said source of current, a mirror which reflects incident light at an angle corresponding to the difference in amplitudes between the instantaneous value of the current of said source and an arbitrary and predetermined value, a first light cell which undergoes a substantial change in impedance when the reflected light makes a predetermined angle with respect to the incident light, a second light cell which similarly undergoes a substantial change in impedance when the reflected light makes a difierent predetermined angle with respect to the incident light, a motor which is coupled to said gain control means, means responsive to a substantial change in impedance of the first light cell for rotating the motor in one direction, and means responsive to a similar change in impedance of the second light cell for rotating the motor in the opposite direction.

' In testimony whereof, I have signed my name to this specification this 24th day of August, 1927.

RUSSELL H. LINDSAY. 

